[gmx-users] the total charge of system is not an integer

Mark Abraham Mark.Abraham at anu.edu.au
Thu Mar 31 09:30:48 CEST 2011


On 31/03/2011 6:17 PM, ahmet yıldırım wrote:
> Dear Tsjerk,
>
> I will ask you one thing but please do not get angry (I know you are 
> not a private tutor but I need your helps).
>
> How do I apply on the files (EDO.itp and TRS.itp) that you said? (or 
> can you suggest a tutorial?)

You'll need to become familiar with the file format, so that you know 
what all the columns of data mean, so you know where the charge groups 
are specified. Chapter 5 of the manual is your first port of call. If 
you have read that and still have questions about detail, please ask on 
the list :-)

Mark

> 2011/3/31 Mark Abraham <Mark.Abraham at anu.edu.au 
> <mailto:Mark.Abraham at anu.edu.au>>
>
>     On 31/03/2011 5:18 PM, ahmet yıldırım wrote:
>>     Dear users,
>>
>>     Before energy minimization step , I performed the preprosessing
>>     step using grompp .
>>     However, there are two note that :
>>
>>     *_NOTE 1 [file topol.top, line 52]:_*
>>       System has non-zero total charge: -1.500000e+01
>
>     This is an integer. See
>     http://en.wikipedia.org/wiki/Scientific_notation#E_notation and
>     http://www.gromacs.org/Documentation/Floating_Point_Arithmetic
>
>>     _*NOTE 2 [file topol.top]:*_
>>       The largest charge group contains 11 atoms.
>>       Since atoms only see each other when the centers of geometry of
>>     the charge
>>       groups they belong to are within the cut-off distance, too
>>     large charge
>>       groups can lead to serious cut-off artifacts.
>>       For efficiency and accuracy, charge group should consist of a
>>     few atoms.
>>       For all-atom force fields use: CH3, CH2, CH, NH2, NH, OH, CO2,
>>     CO, etc.
>
>     See Tsjerk's email.
>
>     Mark
>
>
>>     *
>>     PS: *TRS and EDO are not aminoacid*
>>
>>     _TRS.itp:_*
>>     ..
>>     [ moleculetype ]
>>     ; Name nrexcl
>>     TRS      3
>>
>>     [ atoms ]
>>     ;   nr      type  resnr resid  atom  cgnr   charge     mass
>>          1        OA     1  TRS      O1     1   -0.119  15.9994
>>          2         H     1  TRS     H13     1    0.032   1.0080
>>          3       CH2     1  TRS      C1     1    0.087  14.0270
>>          4      CCl4     1  TRS       C     2    0.055  12.0110
>>          5       CH2     1  TRS      C3     2    0.049  14.0270
>>          6        OA     1  TRS      O3     2   -0.205  15.9994
>>          7         H     1  TRS     H33     2    0.019   1.0080
>>          8        NL     1  TRS       N     2    0.206  14.0067
>>          9         H     1  TRS      H2     2    0.004   1.0080
>>         10         H     1  TRS      H3     2    0.004   1.0080
>>         11         H     1  TRS      H1     2    0.004   1.0080
>>         12       CH2     1  TRS      C2     2    0.050  14.0270
>>         13        OA     1  TRS      O2     2   -0.205  15.9994
>>         14         H     1  TRS     H23     2    0.019   1.0080
>>     ...
>>
>>     _*EDO.itp*_
>>     ...
>>     [ moleculetype ]
>>     ; Name nrexcl
>>     EDO      3
>>
>>     [ atoms ]
>>     ;   nr      type  resnr resid  atom  cgnr   charge     mass
>>          1        OA     1  EDO     OAB     1   -0.111  15.9994
>>          2         H     1  EDO     HAE     1    0.031   1.0080
>>          3       CH2     1  EDO     CAA     1    0.080  14.0270
>>          4       CH2     1  EDO     CAC     1    0.080  14.0270
>>          5        OA     1  EDO     OAD     1   -0.111  15.9994
>>          6         H     1  EDO     HAF     1    0.031   1.0080
>>     ...
>>     _*
>>     topol.top:*_
>>     ..
>>     ; Include water topology
>>     #include "gromos43a1.ff/spc.itp"
>>     #include "TRS.itp"
>>     #include "EDO.itp"
>>     ..
>>     [ molecules ]
>>     ; Compound        #mols
>>     Protein_chain_A     1
>>     Protein_chain_B     1
>>     SOL               185
>>     SOL               143
>>     TRS                1
>>     EDO                1
>>     SOL             44125
>>     *_
>>     Conf.gro:_*
>>     MTA/SAH NUCLEOSIDASE; 5 NUCLEOSIDASE
>>      5354
>>         2GLN      N    1   1.458  -1.158   0.739
>>         2GLN     H1    2   1.520  -1.083   0.763
>>     .......
>>       485HOH    HW1 5333   0.221  -3.864  -2.291
>>       485HOH    HW2 5334   0.303  -3.946  -2.407
>>         1TRS  O1       1  -3.812  -0.471  -2.002
>>         1TRS  H13      2  -3.865  -0.443  -1.922
>>         1TRS  C1       3  -3.672  -0.469  -1.971
>>         1TRS  C        4  -3.635  -0.571  -1.863
>>         1TRS  C3       5  -3.711  -0.547  -1.731
>>         1TRS  O3       6  -3.694  -0.414  -1.679
>>         1TRS  H33      7  -3.746  -0.404  -1.594
>>         1TRS  N        8  -3.673  -0.705  -1.911
>>         1TRS  H2       9  -3.625  -0.725  -1.996
>>         1TRS  H3      10  -3.771  -0.707  -1.927
>>         1TRS  H1      11  -3.649  -0.774  -1.842
>>         1TRS  C2      12  -3.483  -0.573  -1.840
>>         1TRS  O2      13  -3.428  -0.445  -1.806
>>         1TRS  H23     14  -3.470  -0.412  -1.722
>>         1EDO  OAB      1   0.307  -2.792   0.149
>>         1EDO  HAE      2   0.390  -2.826   0.104
>>         1EDO  CAA      3   0.239  -2.901   0.212
>>         1EDO  CAC      4   0.111  -2.851   0.281
>>         1EDO  OAD      5   0.144  -2.763   0.388
>>         1EDO  HAF      6   0.060  -2.731   0.432
>>        8.13100   7.04165  13.54850   0.00000   0.00000  -4.06550  
>>     0.00000   0.00000   0.00000
>>
>>     How can I fixed these notes(note 1 and note 2)?
>>
>>     Thanks in advance
>>     -- 
>>     Ahmet YILDIRIM
>
>
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>
>
> -- 
> Ahmet YILDIRIM

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